1. Field of the Invention
The present invention relates to a gear selector device for a gearbox intended for motor vehicles and of the type which is maneuvered indirectly via a control unit connected to the gear selector device, provided with a pivotably mounted maneuvering column, and with a locking arrangement for locking the maneuvering column in predetermined positions.
In automotive technology it is becoming more and more common, especially in the case of heavy vehicles such as, for example, lorries and buses, to attempt to make the driver's work easier by reducing and simplifying the effort required for changing gear. This is achieved by means of indirect maneuvering of the gearbox, whereby the driver maneuvering a gear selector device so as to cause the latter to emit, as a function of the position, different signals intended to carry out via the servo the actual maneuvering of the gearbox, i.e. to effect engagement and disengagement of gears.
By having a control unit detect the actual driving conditions, such as, for example, speed, acceleration, engaged gear and engine speed, it is possible to further facilitate the work of the driver. The control unit can then calculate which gear should be engaged and can present its suggestion to the driver on a gear indicator. Then, with the aid of the gear selector device, the driver can change gear according to the suggestion or deviate from the suggestion. The gear selector device may also permit a choice between, for example, different semiautomatic or fully automatic predetermined gear programs.
2. Description of the Prior Art
In order to permit simple adjustment of the gear selector device to desired positions, it is known to use a single maneuvering column and to mount the latter pivotably in different planes, for example in a plane parallel to the longitudinal direction of the vehicle and in planes transverse to this plane.
In one embodiment according to U.S. Pat. No. 4,519,266, of the locking arrangement which holds the maneuvering column in different positions is located in connection with the pivot center of the maneuvering column and permits a gear-changing pattern of the type which is customary in manual gearboxes. There are no non-locking positions.
In another design, according to SE-A-8803674-4, the maneuvering column can be adjusted to different positions in a first plane and can be pivoted non-lockingly from these positions transverse to this plane. The locking arrangement which holds the maneuvering column in different longitudinal positions, is in this case designed with a cam curve in the bottom of the housing of the gear selector device, but there is however no possibility of locking the maneuvering column in the lateral direction. Among the disadvantages associated with these known embodiments is the fact that, when a modified gear-changing pattern is required, it is necessary to alter the housing of the gear selector device internally in order to obtain new positions for the maneuvering column. In addition, the locking arrangement competes for space with the sensors which are required for detecting the different positions of the maneuvering column.